The Secret Cave To Gaptooth

Hello guys! There is something that has been bothering me lately. The title explains what. Is there really a cave from Aurora's Basin (The place in Tall Trees) to gaptooth? This is what a guy told me. It is in Aurora's Basin, but it is very hard to find, this sentence may help you: Come out come out wherever you are? (He said that this was said in a trailer before the game came out) And it might be a glitch that takes you to gaptooth, or a Secret cave by rockstar. He said it is somewhere in the river (the water is so shallow you can walk on it) but I havent found anything, so please is this real fake or unconfirmed? By the way this might be the brand new secret location in the upcoming Undead Nightmare DLC.